During network configuration or other network planning exercises, a neighbor cell list may be defined that identifies a plurality of cells that may be capable of supporting communications between a user equipment (UE) and the network. The cells included within the neighbor list may include cells that operate at the frequency that is currently used by the UE, as well as cells that operate at a different frequency that is not currently used by the UE, but that may also support communications between the UE and the network. A neighbor cell list may identify cells in various manners including, for example, by scrambling codes associated with the cells such as in a Code Division Multiple Access (CDMA) based network or by information regarding frequency in use by the cells in a Time Division Multiple Access (TDMA) based network. The neighbor cell list may be utilized, for example, to perform handover of a cell to another cell, or perform cell reselection from one serving/camped cell to another serving/camped cell.
In this regard, the UE may monitor the performance, such as the signal strength, of a first cell that is supporting communications between the UE and the network as well as a number of other cells. Based upon the relative performance of the cells as well as a number of other factors, the UE may be handed over or undergo a cell reselection process from the first cell to another cell included within the neighbor list such that the other cell then begins to support communications between the UE and the network. For example, the UE may be handed over from the first cell to the other cell in instances in which the performance of the other cell exceeds that of the first cell. In instances in which the other cell operates at a different frequency than the first cell, the hand over may result in the communications between the UE and the network not only being supported by a different cell, but also being conducted at a different frequency.
As currently defined by the 3rd Generation Partnership Project (3GPP), however, handover and cell reselection procedures are limited to cells in the neighbor cell list even though the UE may detect one or more cells (referred to as “detected cells”) that are not on the list. By limiting the handover and cell reselection procedures to cells in the neighbor cell list, the network is able to insure that the handover and cell reselection procedures only involve cells that have been determined by the network to be appropriate, such as cells in the same public land mobile network (PLMN), and cells that are inappropriate, such as cells in a different PLMN and/or cells that are barred or reserved for operator use.